includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /**
   9  * Depends on the CacheManager
  10  */
  11 require_once( 'CacheManager.php' );
  12
  13 /** See Database::makeList() */
  14 define( 'LIST_COMMA', 0 );
  15 define( 'LIST_AND', 1 );
  16 define( 'LIST_SET', 2 );
  17 define( 'LIST_NAMES', 3);
  18 define( 'LIST_OR', 4);
  19
  20 /** Number of times to re-try an operation in case of deadlock */
  21 define( 'DEADLOCK_TRIES', 4 );
  22 /** Minimum time to wait before retry, in microseconds */
  23 define( 'DEADLOCK_DELAY_MIN', 500000 );
  24 /** Maximum time to wait before retry */
  25 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  26
  27 class DBObject {
  28         var $mData;
  29
  30         function DBObject($data) {
  31                 $this->mData = $data;
  32         }
  33
  34         function isLOB() {
  35                 return false;
  36         }
  37
  38         function data() {
  39                 return $this->mData;
  40         }
  41 };
  42
  43 /**
  44  * Database abstraction object
  45  * @package MediaWiki
  46  */
  47 class Database {
  48
  49 #------------------------------------------------------------------------------
  50 # Variables
  51 #------------------------------------------------------------------------------
  52         /**#@+
  53          * @private
  54          */
  55         var $mLastQuery = '';
  56
  57         var $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
  58         var $mOut, $mOpened = false;
  59
  60         var $mFailFunction;
  61         var $mTablePrefix;
  62         var $mFlags;
  63         var $mTrxLevel = 0;
  64         var $mErrorCount = 0;
  65         var $mLBInfo = array();
  66         /**#@-*/
  67
  68 #------------------------------------------------------------------------------
  69 # Accessors
  70 #------------------------------------------------------------------------------
  71         # These optionally set a variable and return the previous state
  72
  73         /**
  74          * Fail function, takes a Database as a parameter
  75          * Set to false for default, 1 for ignore errors
  76          */
  77         function failFunction( $function = NULL ) {
  78                 return wfSetVar( $this->mFailFunction, $function );
  79         }
  80
  81         /**
  82          * Output page, used for reporting errors
  83          * FALSE means discard output
  84          */
  85         function &setOutputPage( &$out ) {
  86                 $this->mOut =& $out;
  87         }
  88
  89         /**
  90          * Boolean, controls output of large amounts of debug information
  91          */
  92         function debug( $debug = NULL ) {
  93                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
  94         }
  95
  96         /**
  97          * Turns buffering of SQL result sets on (true) or off (false).
  98          * Default is "on" and it should not be changed without good reasons.
  99          */
 100         function bufferResults( $buffer = NULL ) {
 101                 if ( is_null( $buffer ) ) {
 102                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 103                 } else {
 104                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 105                 }
 106         }
 107
 108         /**
 109          * Turns on (false) or off (true) the automatic generation and sending
 110          * of a "we're sorry, but there has been a database error" page on
 111          * database errors. Default is on (false). When turned off, the
 112          * code should use wfLastErrno() and wfLastError() to handle the
 113          * situation as appropriate.
 114          */
 115         function ignoreErrors( $ignoreErrors = NULL ) {
 116                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 117         }
 118
 119         /**
 120          * The current depth of nested transactions
 121          * @param $level Integer: , default NULL.
 122          */
 123         function trxLevel( $level = NULL ) {
 124                 return wfSetVar( $this->mTrxLevel, $level );
 125         }
 126
 127         /**
 128          * Number of errors logged, only useful when errors are ignored
 129          */
 130         function errorCount( $count = NULL ) {
 131                 return wfSetVar( $this->mErrorCount, $count );
 132         }
 133
 134         /**
 135          * Properties passed down from the server info array of the load balancer
 136          */
 137         function getLBInfo( $name = NULL ) {
 138                 if ( is_null( $name ) ) {
 139                         return $this->mLBInfo;
 140                 } else {
 141                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 142                                 return $this->mLBInfo[$name];
 143                         } else {
 144                                 return NULL;
 145                         }
 146                 }
 147         }
 148
 149         function setLBInfo( $name, $value = NULL ) {
 150                 if ( is_null( $value ) ) {
 151                         $this->mLBInfo = $name;
 152                 } else {
 153                         $this->mLBInfo[$name] = $value;
 154                 }
 155         }
 156
 157         /**#@+
 158          * Get function
 159          */
 160         function lastQuery() { return $this->mLastQuery; }
 161         function isOpen() { return $this->mOpened; }
 162         /**#@-*/
 163
 164         function setFlag( $flag ) {
 165                 $this->mFlags |= $flag;
 166         }
 167
 168         function clearFlag( $flag ) {
 169                 $this->mFlags &= ~$flag;
 170         }
 171
 172         function getFlag( $flag ) {
 173                 return !!($this->mFlags & $flag);
 174         }
 175
 176 #------------------------------------------------------------------------------
 177 # Other functions
 178 #------------------------------------------------------------------------------
 179
 180         /**@{{
 181          * @param string $server database server host
 182          * @param string $user database user name
 183          * @param string $password database user password
 184          * @param string $dbname database name
 185          */
 186
 187         /**
 188          * @param failFunction
 189          * @param $flags
 190          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 191          */
 192         function Database( $server = false, $user = false, $password = false, $dbName = false,
 193                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 194
 195                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 196                 # Can't get a reference if it hasn't been set yet
 197                 if ( !isset( $wgOut ) ) {
 198                         $wgOut = NULL;
 199                 }
 200                 $this->mOut =& $wgOut;
 201
 202                 $this->mFailFunction = $failFunction;
 203                 $this->mFlags = $flags;
 204
 205                 if ( $this->mFlags & DBO_DEFAULT ) {
 206                         if ( $wgCommandLineMode ) {
 207                                 $this->mFlags &= ~DBO_TRX;
 208                         } else {
 209                                 $this->mFlags |= DBO_TRX;
 210                         }
 211                 }
 212
 213                 /*
 214                 // Faster read-only access
 215                 if ( wfReadOnly() ) {
 216                         $this->mFlags |= DBO_PERSISTENT;
 217                         $this->mFlags &= ~DBO_TRX;
 218                 }*/
 219
 220                 /** Get the default table prefix*/
 221                 if ( $tablePrefix == 'get from global' ) {
 222                         $this->mTablePrefix = $wgDBprefix;
 223                 } else {
 224                         $this->mTablePrefix = $tablePrefix;
 225                 }
 226
 227                 if ( $server ) {
 228                         $this->open( $server, $user, $password, $dbName );
 229                 }
 230         }
 231
 232         /**
 233          * @static
 234          * @param failFunction
 235          * @param $flags
 236          */
 237         function newFromParams( $server, $user, $password, $dbName,
 238                 $failFunction = false, $flags = 0 )
 239         {
 240                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 241         }
 242
 243         /**
 244          * Usually aborts on failure
 245          * If the failFunction is set to a non-zero integer, returns success
 246          */
 247         function open( $server, $user, $password, $dbName ) {
 248                 global $wguname;
 249
 250                 # Test for missing mysql.so
 251                 # First try to load it
 252                 if (!@extension_loaded('mysql')) {
 253                         @dl('mysql.so');
 254                 }
 255
 256                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 257                 if ( !function_exists( 'mysql_connect' ) ) {
 258                         wfDie( "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 259                 }
 260
 261                 $this->close();
 262                 $this->mServer = $server;
 263                 $this->mUser = $user;
 264                 $this->mPassword = $password;
 265                 $this->mDBname = $dbName;
 266
 267                 $success = false;
 268
 269                 if ( $this->mFlags & DBO_PERSISTENT ) {
 270                         @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 271                 } else {
 272                         # Create a new connection...
 273                         @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 274                 }
 275
 276                 if ( $dbName != '' ) {
 277                         if ( $this->mConn !== false ) {
 278                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 279                                 if ( !$success ) {
 280                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 281                                                 "from client host {$wguname['nodename']}\n";
 282                                         wfDebug( $error );
 283                                 }
 284                         } else {
 285                                 wfDebug( "DB connection error\n" );
 286                                 wfDebug( "Server: $server, User: $user, Password: " .
 287                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 288                                 $success = false;
 289                         }
 290                 } else {
 291                         # Delay USE query
 292                         $success = (bool)$this->mConn;
 293                 }
 294
 295                 if ( !$success ) {
 296                         $this->reportConnectionError();
 297                 }
 298
 299                 global $wgDBmysql5;
 300                 if( $wgDBmysql5 ) {
 301                         // Tell the server we're communicating with it in UTF-8.
 302                         // This may engage various charset conversions.
 303                         $this->query( 'SET NAMES utf8' );
 304                 }
 305
 306                 $this->mOpened = $success;
 307                 return $success;
 308         }
 309         /**@}}*/
 310
 311         /**
 312          * Closes a database connection.
 313          * if it is open : commits any open transactions
 314          *
 315          * @return bool operation success. true if already closed.
 316          */
 317         function close()
 318         {
 319                 $this->mOpened = false;
 320                 if ( $this->mConn ) {
 321                         if ( $this->trxLevel() ) {
 322                                 $this->immediateCommit();
 323                         }
 324                         return mysql_close( $this->mConn );
 325                 } else {
 326                         return true;
 327                 }
 328         }
 329
 330         /**
 331          * @private
 332          * @param string $error fallback error message, used if none is given by MySQL
 333          */
 334         function reportConnectionError( $error = 'Unknown error' ) {
 335                 $myError = $this->lastError();
 336                 if ( $myError ) {
 337                         $error = $myError;
 338                 }
 339
 340                 if ( $this->mFailFunction ) {
 341                         if ( !is_int( $this->mFailFunction ) ) {
 342                                 $ff = $this->mFailFunction;
 343                                 $ff( $this, $error );
 344                         }
 345                 } else {
 346                         wfEmergencyAbort( $this, $error );
 347                 }
 348         }
 349
 350         /**
 351          * Usually aborts on failure
 352          * If errors are explicitly ignored, returns success
 353          */
 354         function query( $sql, $fname = '', $tempIgnore = false ) {
 355                 global $wgProfiling;
 356
 357                 if ( $wgProfiling ) {
 358                         # generalizeSQL will probably cut down the query to reasonable
 359                         # logging size most of the time. The substr is really just a sanity check.
 360
 361                         # Who's been wasting my precious column space? -- TS
 362                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 363
 364                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 365                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 366                                 $totalProf = 'Database::query';
 367                         } else {
 368                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 369                                 $totalProf = 'Database::query-master';
 370                         }
 371                         wfProfileIn( $totalProf );
 372                         wfProfileIn( $queryProf );
 373                 }
 374
 375                 $this->mLastQuery = $sql;
 376
 377                 # Add a comment for easy SHOW PROCESSLIST interpretation
 378                 if ( $fname ) {
 379                         $commentedSql = preg_replace("/\s/", " /* $fname */ ", $sql, 1);
 380                 } else {
 381                         $commentedSql = $sql;
 382                 }
 383
 384                 # If DBO_TRX is set, start a transaction
 385                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() && $sql != 'BEGIN' ) {
 386                         $this->begin();
 387                 }
 388
 389                 if ( $this->debug() ) {
 390                         $sqlx = substr( $commentedSql, 0, 500 );
 391                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 392                         wfDebug( "SQL: $sqlx\n" );
 393                 }
 394
 395                 # Do the query and handle errors
 396                 $ret = $this->doQuery( $commentedSql );
 397
 398                 # Try reconnecting if the connection was lost
 399                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 400                         # Transaction is gone, like it or not
 401                         $this->mTrxLevel = 0;
 402                         wfDebug( "Connection lost, reconnecting...\n" );
 403                         if ( $this->ping() ) {
 404                                 wfDebug( "Reconnected\n" );
 405                                 $ret = $this->doQuery( $commentedSql );
 406                         } else {
 407                                 wfDebug( "Failed\n" );
 408                         }
 409                 }
 410
 411                 if ( false === $ret ) {
 412                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 413                 }
 414
 415                 if ( $wgProfiling ) {
 416                         wfProfileOut( $queryProf );
 417                         wfProfileOut( $totalProf );
 418                 }
 419                 return $ret;
 420         }
 421
 422         /**
 423          * The DBMS-dependent part of query()
 424          * @param string $sql SQL query.
 425          */
 426         function doQuery( $sql ) {
 427                 if( $this->bufferResults() ) {
 428                         $ret = mysql_query( $sql, $this->mConn );
 429                 } else {
 430                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 431                 }
 432                 return $ret;
 433         }
 434
 435         /**
 436          * @param $error
 437          * @param $errno
 438          * @param $sql
 439          * @param string $fname
 440          * @param bool $tempIgnore
 441          */
 442         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 443                 global $wgCommandLineMode, $wgFullyInitialised, $wgColorErrors;
 444                 # Ignore errors during error handling to avoid infinite recursion
 445                 $ignore = $this->ignoreErrors( true );
 446                 ++$this->mErrorCount;
 447
 448                 if( $ignore || $tempIgnore ) {
 449                         wfDebug("SQL ERROR (ignored): $error\n");
 450                 } else {
 451                         $sql1line = str_replace( "\n", "\\n", $sql );
 452                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 453                         wfDebug("SQL ERROR: " . $error . "\n");
 454                         if ( $wgCommandLineMode || !$this->mOut || empty( $wgFullyInitialised ) ) {
 455                                 $message = "A database error has occurred\n" .
 456                                   "Query: $sql\n" .
 457                                   "Function: $fname\n" .
 458                                   "Error: $errno $error\n";
 459                                 if ( !$wgCommandLineMode ) {
 460                                         $message = nl2br( $message );
 461                                 }
 462                                 if( $wgCommandLineMode && $wgColorErrors && !wfIsWindows() && posix_isatty(1) ) {
 463                                         $color = 31; // bright red!
 464                                         $message = "\x1b[1;{$color}m{$message}\x1b[0m";
 465                                 }
 466                                 wfDebugDieBacktrace( $message );
 467                         } else {
 468                                 // this calls wfAbruptExit()
 469                                 $this->mOut->databaseError( $fname, $sql, $error, $errno );
 470                         }
 471                 }
 472                 $this->ignoreErrors( $ignore );
 473         }
 474
 475
 476         /**
 477          * Intended to be compatible with the PEAR::DB wrapper functions.
 478          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 479          *
 480          * ? = scalar value, quoted as necessary
 481          * ! = raw SQL bit (a function for instance)
 482          * & = filename; reads the file and inserts as a blob
 483          *     (we don't use this though...)
 484          */
 485         function prepare( $sql, $func = 'Database::prepare' ) {
 486                 /* MySQL doesn't support prepared statements (yet), so just
 487                    pack up the query for reference. We'll manually replace
 488                    the bits later. */
 489                 return array( 'query' => $sql, 'func' => $func );
 490         }
 491
 492         function freePrepared( $prepared ) {
 493                 /* No-op for MySQL */
 494         }
 495
 496         /**
 497          * Execute a prepared query with the various arguments
 498          * @param string $prepared the prepared sql
 499          * @param mixed $args Either an array here, or put scalars as varargs
 500          */
 501         function execute( $prepared, $args = null ) {
 502                 if( !is_array( $args ) ) {
 503                         # Pull the var args
 504                         $args = func_get_args();
 505                         array_shift( $args );
 506                 }
 507                 $sql = $this->fillPrepared( $prepared['query'], $args );
 508                 return $this->query( $sql, $prepared['func'] );
 509         }
 510
 511         /**
 512          * Prepare & execute an SQL statement, quoting and inserting arguments
 513          * in the appropriate places.
 514          * @param string $query
 515          * @param string $args ...
 516          */
 517         function safeQuery( $query, $args = null ) {
 518                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 519                 if( !is_array( $args ) ) {
 520                         # Pull the var args
 521                         $args = func_get_args();
 522                         array_shift( $args );
 523                 }
 524                 $retval = $this->execute( $prepared, $args );
 525                 $this->freePrepared( $prepared );
 526                 return $retval;
 527         }
 528
 529         /**
 530          * For faking prepared SQL statements on DBs that don't support
 531          * it directly.
 532          * @param string $preparedSql - a 'preparable' SQL statement
 533          * @param array $args - array of arguments to fill it with
 534          * @return string executable SQL
 535          */
 536         function fillPrepared( $preparedQuery, $args ) {
 537                 reset( $args );
 538                 $this->preparedArgs =& $args;
 539                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 540                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 541         }
 542
 543         /**
 544          * preg_callback func for fillPrepared()
 545          * The arguments should be in $this->preparedArgs and must not be touched
 546          * while we're doing this.
 547          *
 548          * @param array $matches
 549          * @return string
 550          * @private
 551          */
 552         function fillPreparedArg( $matches ) {
 553                 switch( $matches[1] ) {
 554                         case '\\?': return '?';
 555                         case '\\!': return '!';
 556                         case '\\&': return '&';
 557                 }
 558                 list( $n, $arg ) = each( $this->preparedArgs );
 559                 switch( $matches[1] ) {
 560                         case '?': return $this->addQuotes( $arg );
 561                         case '!': return $arg;
 562                         case '&':
 563                                 # return $this->addQuotes( file_get_contents( $arg ) );
 564                                 wfDebugDieBacktrace( '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 565                         default:
 566                                 wfDebugDieBacktrace( 'Received invalid match. This should never happen!' );
 567                 }
 568         }
 569
 570         /**#@+
 571          * @param mixed $res A SQL result
 572          */
 573         /**
 574          * Free a result object
 575          */
 576         function freeResult( $res ) {
 577                 if ( !@/**/mysql_free_result( $res ) ) {
 578                         wfDebugDieBacktrace( "Unable to free MySQL result\n" );
 579                 }
 580         }
 581
 582         /**
 583          * Fetch the next row from the given result object, in object form
 584          */
 585         function fetchObject( $res ) {
 586                 @/**/$row = mysql_fetch_object( $res );
 587                 if( mysql_errno() ) {
 588                         wfDebugDieBacktrace( 'Error in fetchObject(): ' . htmlspecialchars( mysql_error() ) );
 589                 }
 590                 return $row;
 591         }
 592
 593         /**
 594          * Fetch the next row from the given result object
 595          * Returns an array
 596          */
 597         function fetchRow( $res ) {
 598                 @/**/$row = mysql_fetch_array( $res );
 599                 if (mysql_errno() ) {
 600                         wfDebugDieBacktrace( 'Error in fetchRow(): ' . htmlspecialchars( mysql_error() ) );
 601                 }
 602                 return $row;
 603         }
 604
 605         /**
 606          * Get the number of rows in a result object
 607          */
 608         function numRows( $res ) {
 609                 @/**/$n = mysql_num_rows( $res );
 610                 if( mysql_errno() ) {
 611                         wfDebugDieBacktrace( 'Error in numRows(): ' . htmlspecialchars( mysql_error() ) );
 612                 }
 613                 return $n;
 614         }
 615
 616         /**
 617          * Get the number of fields in a result object
 618          * See documentation for mysql_num_fields()
 619          */
 620         function numFields( $res ) { return mysql_num_fields( $res ); }
 621
 622         /**
 623          * Get a field name in a result object
 624          * See documentation for mysql_field_name():
 625          * http://www.php.net/mysql_field_name
 626          */
 627         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 628
 629         /**
 630          * Get the inserted value of an auto-increment row
 631          *
 632          * The value inserted should be fetched from nextSequenceValue()
 633          *
 634          * Example:
 635          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 636          * $dbw->insert('page',array('page_id' => $id));
 637          * $id = $dbw->insertId();
 638          */
 639         function insertId() { return mysql_insert_id( $this->mConn ); }
 640
 641         /**
 642          * Change the position of the cursor in a result object
 643          * See mysql_data_seek()
 644          */
 645         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 646
 647         /**
 648          * Get the last error number
 649          * See mysql_errno()
 650          */
 651         function lastErrno() {
 652                 if ( $this->mConn ) {
 653                         return mysql_errno( $this->mConn );
 654                 } else {
 655                         return mysql_errno();
 656                 }
 657         }
 658
 659         /**
 660          * Get a description of the last error
 661          * See mysql_error() for more details
 662          */
 663         function lastError() {
 664                 if ( $this->mConn ) {
 665                         # Even if it's non-zero, it can still be invalid
 666                         wfSuppressWarnings();
 667                         $error = mysql_error( $this->mConn );
 668                         if ( !$error ) {
 669                                 $error = mysql_error();
 670                         }
 671                         wfRestoreWarnings();
 672                 } else {
 673                         $error = mysql_error();
 674                 }
 675                 if( $error ) {
 676                         $error .= ' (' . $this->mServer . ')';
 677                 }
 678                 return $error;
 679         }
 680         /**
 681          * Get the number of rows affected by the last write query
 682          * See mysql_affected_rows() for more details
 683          */
 684         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 685         /**#@-*/ // end of template : @param $result
 686
 687         /**
 688          * Simple UPDATE wrapper
 689          * Usually aborts on failure
 690          * If errors are explicitly ignored, returns success
 691          *
 692          * This function exists for historical reasons, Database::update() has a more standard
 693          * calling convention and feature set
 694          */
 695         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 696         {
 697                 $table = $this->tableName( $table );
 698                 $sql = "UPDATE $table SET $var = '" .
 699                   $this->strencode( $value ) . "' WHERE ($cond)";
 700                 return (bool)$this->query( $sql, $fname );
 701         }
 702
 703         /**
 704          * Simple SELECT wrapper, returns a single field, input must be encoded
 705          * Usually aborts on failure
 706          * If errors are explicitly ignored, returns FALSE on failure
 707          */
 708         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 709                 if ( !is_array( $options ) ) {
 710                         $options = array( $options );
 711                 }
 712                 $options['LIMIT'] = 1;
 713
 714                 $res = $this->select( $table, $var, $cond, $fname, $options );
 715                 if ( $res === false || !$this->numRows( $res ) ) {
 716                         return false;
 717                 }
 718                 $row = $this->fetchRow( $res );
 719                 if ( $row !== false ) {
 720                         $this->freeResult( $res );
 721                         return $row[0];
 722                 } else {
 723                         return false;
 724                 }
 725         }
 726
 727         /**
 728          * Returns an optional USE INDEX clause to go after the table, and a
 729          * string to go at the end of the query
 730          *
 731          * @private
 732          *
 733          * @param array $options an associative array of options to be turned into
 734          *              an SQL query, valid keys are listed in the function.
 735          * @return array
 736          */
 737         function makeSelectOptions( $options ) {
 738                 $tailOpts = '';
 739                 $startOpts = '';
 740
 741                 $noKeyOptions = array();
 742                 foreach ( $options as $key => $option ) {
 743                         if ( is_numeric( $key ) ) {
 744                                 $noKeyOptions[$option] = true;
 745                         }
 746                 }
 747
 748                 if ( isset( $options['GROUP BY'] ) ) $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 749                 if ( isset( $options['ORDER BY'] ) ) $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 750
 751                 if (isset($options['LIMIT'])) {
 752                         $tailOpts .= $this->limitResult('', $options['LIMIT'],
 753                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 754                 }
 755
 756                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
 757                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
 758                 if ( isset( $noKeyOptions['DISTINCT'] ) && isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 759
 760                 # Various MySQL extensions
 761                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
 762                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
 763                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
 764                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
 765                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
 766                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
 767                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
 768
 769                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
 770                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
 771                 } else {
 772                         $useIndex = '';
 773                 }
 774
 775                 return array( $startOpts, $useIndex, $tailOpts );
 776         }
 777
 778         /**
 779          * SELECT wrapper
 780          */
 781         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
 782         {
 783                 if( is_array( $vars ) ) {
 784                         $vars = implode( ',', $vars );
 785                 }
 786                 if( !is_array( $options ) ) {
 787                         $options = array( $options );
 788                 }
 789                 if( is_array( $table ) ) {
 790                         if ( @is_array( $options['USE INDEX'] ) )
 791                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
 792                         else
 793                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
 794                 } elseif ($table!='') {
 795                         $from = ' FROM ' . $this->tableName( $table );
 796                 } else {
 797                         $from = '';
 798                 }
 799
 800                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $options );
 801
 802                 if( !empty( $conds ) ) {
 803                         if ( is_array( $conds ) ) {
 804                                 $conds = $this->makeList( $conds, LIST_AND );
 805                         }
 806                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $tailOpts";
 807                 } else {
 808                         $sql = "SELECT $startOpts $vars $from $useIndex $tailOpts";
 809                 }
 810
 811                 return $this->query( $sql, $fname );
 812         }
 813
 814         /**
 815          * Single row SELECT wrapper
 816          * Aborts or returns FALSE on error
 817          *
 818          * $vars: the selected variables
 819          * $conds: a condition map, terms are ANDed together.
 820          *   Items with numeric keys are taken to be literal conditions
 821          * Takes an array of selected variables, and a condition map, which is ANDed
 822          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
 823          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
 824          * $obj- >page_id is the ID of the Astronomy article
 825          *
 826          * @todo migrate documentation to phpdocumentor format
 827          */
 828         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
 829                 $options['LIMIT'] = 1;
 830                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 831                 if ( $res === false )
 832                         return false;
 833                 if ( !$this->numRows($res) ) {
 834                         $this->freeResult($res);
 835                         return false;
 836                 }
 837                 $obj = $this->fetchObject( $res );
 838                 $this->freeResult( $res );
 839                 return $obj;
 840
 841         }
 842
 843         /**
 844          * Removes most variables from an SQL query and replaces them with X or N for numbers.
 845          * It's only slightly flawed. Don't use for anything important.
 846          *
 847          * @param string $sql A SQL Query
 848          * @static
 849          */
 850         function generalizeSQL( $sql ) {
 851                 # This does the same as the regexp below would do, but in such a way
 852                 # as to avoid crashing php on some large strings.
 853                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
 854
 855                 $sql = str_replace ( "\\\\", '', $sql);
 856                 $sql = str_replace ( "\\'", '', $sql);
 857                 $sql = str_replace ( "\\\"", '', $sql);
 858                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
 859                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
 860
 861                 # All newlines, tabs, etc replaced by single space
 862                 $sql = preg_replace ( "/\s+/", ' ', $sql);
 863
 864                 # All numbers => N
 865                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
 866
 867                 return $sql;
 868         }
 869
 870         /**
 871          * Determines whether a field exists in a table
 872          * Usually aborts on failure
 873          * If errors are explicitly ignored, returns NULL on failure
 874          */
 875         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
 876                 $table = $this->tableName( $table );
 877                 $res = $this->query( 'DESCRIBE '.$table, $fname );
 878                 if ( !$res ) {
 879                         return NULL;
 880                 }
 881
 882                 $found = false;
 883
 884                 while ( $row = $this->fetchObject( $res ) ) {
 885                         if ( $row->Field == $field ) {
 886                                 $found = true;
 887                                 break;
 888                         }
 889                 }
 890                 return $found;
 891         }
 892
 893         /**
 894          * Determines whether an index exists
 895          * Usually aborts on failure
 896          * If errors are explicitly ignored, returns NULL on failure
 897          */
 898         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
 899                 $info = $this->indexInfo( $table, $index, $fname );
 900                 if ( is_null( $info ) ) {
 901                         return NULL;
 902                 } else {
 903                         return $info !== false;
 904                 }
 905         }
 906
 907
 908         /**
 909          * Get information about an index into an object
 910          * Returns false if the index does not exist
 911          */
 912         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
 913                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 914                 # SHOW INDEX should work for 3.x and up:
 915                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 916                 $table = $this->tableName( $table );
 917                 $sql = 'SHOW INDEX FROM '.$table;
 918                 $res = $this->query( $sql, $fname );
 919                 if ( !$res ) {
 920                         return NULL;
 921                 }
 922
 923                 while ( $row = $this->fetchObject( $res ) ) {
 924                         if ( $row->Key_name == $index ) {
 925                                 return $row;
 926                         }
 927                 }
 928                 return false;
 929         }
 930
 931         /**
 932          * Query whether a given table exists
 933          */
 934         function tableExists( $table ) {
 935                 $table = $this->tableName( $table );
 936                 $old = $this->ignoreErrors( true );
 937                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
 938                 $this->ignoreErrors( $old );
 939                 if( $res ) {
 940                         $this->freeResult( $res );
 941                         return true;
 942                 } else {
 943                         return false;
 944                 }
 945         }
 946
 947         /**
 948          * mysql_fetch_field() wrapper
 949          * Returns false if the field doesn't exist
 950          *
 951          * @param $table
 952          * @param $field
 953          */
 954         function fieldInfo( $table, $field ) {
 955                 $table = $this->tableName( $table );
 956                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
 957                 $n = mysql_num_fields( $res );
 958                 for( $i = 0; $i < $n; $i++ ) {
 959                         $meta = mysql_fetch_field( $res, $i );
 960                         if( $field == $meta->name ) {
 961                                 return $meta;
 962                         }
 963                 }
 964                 return false;
 965         }
 966
 967         /**
 968          * mysql_field_type() wrapper
 969          */
 970         function fieldType( $res, $index ) {
 971                 return mysql_field_type( $res, $index );
 972         }
 973
 974         /**
 975          * Determines if a given index is unique
 976          */
 977         function indexUnique( $table, $index ) {
 978                 $indexInfo = $this->indexInfo( $table, $index );
 979                 if ( !$indexInfo ) {
 980                         return NULL;
 981                 }
 982                 return !$indexInfo->Non_unique;
 983         }
 984
 985         /**
 986          * INSERT wrapper, inserts an array into a table
 987          *
 988          * $a may be a single associative array, or an array of these with numeric keys, for
 989          * multi-row insert.
 990          *
 991          * Usually aborts on failure
 992          * If errors are explicitly ignored, returns success
 993          */
 994         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
 995                 # No rows to insert, easy just return now
 996                 if ( !count( $a ) ) {
 997                         return true;
 998                 }
 999
1000                 $table = $this->tableName( $table );
1001                 if ( !is_array( $options ) ) {
1002                         $options = array( $options );
1003                 }
1004                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1005                         $multi = true;
1006                         $keys = array_keys( $a[0] );
1007                 } else {
1008                         $multi = false;
1009                         $keys = array_keys( $a );
1010                 }
1011
1012                 $sql = 'INSERT ' . implode( ' ', $options ) .
1013                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1014
1015                 if ( $multi ) {
1016                         $first = true;
1017                         foreach ( $a as $row ) {
1018                                 if ( $first ) {
1019                                         $first = false;
1020                                 } else {
1021                                         $sql .= ',';
1022                                 }
1023                                 $sql .= '(' . $this->makeList( $row ) . ')';
1024                         }
1025                 } else {
1026                         $sql .= '(' . $this->makeList( $a ) . ')';
1027                 }
1028                 return (bool)$this->query( $sql, $fname );
1029         }
1030
1031         /**
1032          * Make UPDATE options for the Database::update function
1033          *
1034          * @private
1035          * @param array $options The options passed to Database::update
1036          * @return string
1037          */
1038         function makeUpdateOptions( $options ) {
1039                 if( !is_array( $options ) ) {
1040                         $options = array( $options );
1041                 }
1042                 $opts = array();
1043                 if ( in_array( 'LOW_PRIORITY', $options ) )
1044                         $opts[] = $this->lowPriorityOption();
1045                 if ( in_array( 'IGNORE', $options ) )
1046                         $opts[] = 'IGNORE';
1047                 return implode(' ', $opts);
1048         }
1049
1050         /**
1051          * UPDATE wrapper, takes a condition array and a SET array
1052          *
1053          * @param string $table  The table to UPDATE
1054          * @param array  $values An array of values to SET
1055          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1056          * @param string $fname  The Class::Function calling this function
1057          *                       (for the log)
1058          * @param array  $options An array of UPDATE options, can be one or
1059          *                        more of IGNORE, LOW_PRIORITY
1060          */
1061         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1062                 $table = $this->tableName( $table );
1063                 $opts = $this->makeUpdateOptions( $options );
1064                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1065                 if ( $conds != '*' ) {
1066                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1067                 }
1068                 $this->query( $sql, $fname );
1069         }
1070
1071         /**
1072          * Makes a wfStrencoded list from an array
1073          * $mode:
1074          *        LIST_COMMA         - comma separated, no field names
1075          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1076          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1077          *        LIST_SET           - comma separated with field names, like a SET clause
1078          *        LIST_NAMES         - comma separated field names
1079          */
1080         function makeList( $a, $mode = LIST_COMMA ) {
1081                 if ( !is_array( $a ) ) {
1082                         wfDebugDieBacktrace( 'Database::makeList called with incorrect parameters' );
1083                 }
1084
1085                 $first = true;
1086                 $list = '';
1087                 foreach ( $a as $field => $value ) {
1088                         if ( !$first ) {
1089                                 if ( $mode == LIST_AND ) {
1090                                         $list .= ' AND ';
1091                                 } elseif($mode == LIST_OR) {
1092                                         $list .= ' OR ';
1093                                 } else {
1094                                         $list .= ',';
1095                                 }
1096                         } else {
1097                                 $first = false;
1098                         }
1099                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1100                                 $list .= "($value)";
1101                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array ($value) ) {
1102                                 $list .= $field." IN (".$this->makeList($value).") ";
1103                         } else {
1104                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1105                                         $list .= "$field = ";
1106                                 }
1107                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1108                         }
1109                 }
1110                 return $list;
1111         }
1112
1113         /**
1114          * Change the current database
1115          */
1116         function selectDB( $db ) {
1117                 $this->mDBname = $db;
1118                 return mysql_select_db( $db, $this->mConn );
1119         }
1120
1121         /**
1122          * Format a table name ready for use in constructing an SQL query
1123          *
1124          * This does two important things: it quotes table names which as necessary,
1125          * and it adds a table prefix if there is one.
1126          *
1127          * All functions of this object which require a table name call this function
1128          * themselves. Pass the canonical name to such functions. This is only needed
1129          * when calling query() directly.
1130          *
1131          * @param string $name database table name
1132          */
1133         function tableName( $name ) {
1134                 global $wgSharedDB;
1135                 # Skip quoted literals
1136                 if ( $name{0} != '`' ) {
1137                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1138                                 $name = "{$this->mTablePrefix}$name";
1139                         }
1140                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1141                                 $name = "`$wgSharedDB`.`$name`";
1142                         } else {
1143                                 # Standard quoting
1144                                 $name = "`$name`";
1145                         }
1146                 }
1147                 return $name;
1148         }
1149
1150         /**
1151          * Fetch a number of table names into an array
1152          * This is handy when you need to construct SQL for joins
1153          *
1154          * Example:
1155          * extract($dbr->tableNames('user','watchlist'));
1156          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1157          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1158          */
1159         function tableNames() {
1160                 $inArray = func_get_args();
1161                 $retVal = array();
1162                 foreach ( $inArray as $name ) {
1163                         $retVal[$name] = $this->tableName( $name );
1164                 }
1165                 return $retVal;
1166         }
1167
1168         /**
1169          * @private
1170          */
1171         function tableNamesWithUseIndex( $tables, $use_index ) {
1172                 $ret = array();
1173
1174                 foreach ( $tables as $table )
1175                         if ( @$use_index[$table] !== null )
1176                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1177                         else
1178                                 $ret[] = $this->tableName( $table );
1179
1180                 return implode( ',', $ret );
1181         }
1182
1183         /**
1184          * Wrapper for addslashes()
1185          * @param string $s String to be slashed.
1186          * @return string slashed string.
1187          */
1188         function strencode( $s ) {
1189                 return addslashes( $s );
1190         }
1191
1192         /**
1193          * If it's a string, adds quotes and backslashes
1194          * Otherwise returns as-is
1195          */
1196         function addQuotes( $s ) {
1197                 if ( is_null( $s ) ) {
1198                         return 'NULL';
1199                 } else {
1200                         # This will also quote numeric values. This should be harmless,
1201                         # and protects against weird problems that occur when they really
1202                         # _are_ strings such as article titles and string->number->string
1203                         # conversion is not 1:1.
1204                         return "'" . $this->strencode( $s ) . "'";
1205                 }
1206         }
1207
1208         /**
1209          * Escape string for safe LIKE usage
1210          */
1211         function escapeLike( $s ) {
1212                 $s=$this->strencode( $s );
1213                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1214                 return $s;
1215         }
1216
1217         /**
1218          * Returns an appropriately quoted sequence value for inserting a new row.
1219          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1220          * subclass will return an integer, and save the value for insertId()
1221          */
1222         function nextSequenceValue( $seqName ) {
1223                 return NULL;
1224         }
1225
1226         /**
1227          * USE INDEX clause
1228          * PostgreSQL doesn't have them and returns ""
1229          */
1230         function useIndexClause( $index ) {
1231                 return "FORCE INDEX ($index)";
1232         }
1233
1234         /**
1235          * REPLACE query wrapper
1236          * PostgreSQL simulates this with a DELETE followed by INSERT
1237          * $row is the row to insert, an associative array
1238          * $uniqueIndexes is an array of indexes. Each element may be either a
1239          * field name or an array of field names
1240          *
1241          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1242          * However if you do this, you run the risk of encountering errors which wouldn't have
1243          * occurred in MySQL
1244          *
1245          * @todo migrate comment to phodocumentor format
1246          */
1247         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1248                 $table = $this->tableName( $table );
1249
1250                 # Single row case
1251                 if ( !is_array( reset( $rows ) ) ) {
1252                         $rows = array( $rows );
1253                 }
1254
1255                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1256                 $first = true;
1257                 foreach ( $rows as $row ) {
1258                         if ( $first ) {
1259                                 $first = false;
1260                         } else {
1261                                 $sql .= ',';
1262                         }
1263                         $sql .= '(' . $this->makeList( $row ) . ')';
1264                 }
1265                 return $this->query( $sql, $fname );
1266         }
1267
1268         /**
1269          * DELETE where the condition is a join
1270          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1271          *
1272          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1273          * join condition matches, set $conds='*'
1274          *
1275          * DO NOT put the join condition in $conds
1276          *
1277          * @param string $delTable The table to delete from.
1278          * @param string $joinTable The other table.
1279          * @param string $delVar The variable to join on, in the first table.
1280          * @param string $joinVar The variable to join on, in the second table.
1281          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1282          */
1283         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1284                 if ( !$conds ) {
1285                         wfDebugDieBacktrace( 'Database::deleteJoin() called with empty $conds' );
1286                 }
1287
1288                 $delTable = $this->tableName( $delTable );
1289                 $joinTable = $this->tableName( $joinTable );
1290                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1291                 if ( $conds != '*' ) {
1292                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1293                 }
1294
1295                 return $this->query( $sql, $fname );
1296         }
1297
1298         /**
1299          * Returns the size of a text field, or -1 for "unlimited"
1300          */
1301         function textFieldSize( $table, $field ) {
1302                 $table = $this->tableName( $table );
1303                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1304                 $res = $this->query( $sql, 'Database::textFieldSize' );
1305                 $row = $this->fetchObject( $res );
1306                 $this->freeResult( $res );
1307
1308                 if ( preg_match( "/\((.*)\)/", $row->Type, $m ) ) {
1309                         $size = $m[1];
1310                 } else {
1311                         $size = -1;
1312                 }
1313                 return $size;
1314         }
1315
1316         /**
1317          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1318          */
1319         function lowPriorityOption() {
1320                 return 'LOW_PRIORITY';
1321         }
1322
1323         /**
1324          * DELETE query wrapper
1325          *
1326          * Use $conds == "*" to delete all rows
1327          */
1328         function delete( $table, $conds, $fname = 'Database::delete' ) {
1329                 if ( !$conds ) {
1330                         wfDebugDieBacktrace( 'Database::delete() called with no conditions' );
1331                 }
1332                 $table = $this->tableName( $table );
1333                 $sql = "DELETE FROM $table";
1334                 if ( $conds != '*' ) {
1335                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1336                 }
1337                 return $this->query( $sql, $fname );
1338         }
1339
1340         /**
1341          * INSERT SELECT wrapper
1342          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1343          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1344          * $conds may be "*" to copy the whole table
1345          * srcTable may be an array of tables.
1346          */
1347         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1348                 $insertOptions = array(), $selectOptions = array() )
1349         {
1350                 $destTable = $this->tableName( $destTable );
1351                 if ( is_array( $insertOptions ) ) {
1352                         $insertOptions = implode( ' ', $insertOptions );
1353                 }
1354                 if( !is_array( $selectOptions ) ) {
1355                         $selectOptions = array( $selectOptions );
1356                 }
1357                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1358                 if( is_array( $srcTable ) ) {
1359                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1360                 } else {
1361                         $srcTable = $this->tableName( $srcTable );
1362                 }
1363                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1364                         " SELECT $startOpts " . implode( ',', $varMap ) .
1365                         " FROM $srcTable $useIndex ";
1366                 if ( $conds != '*' ) {
1367                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1368                 }
1369                 $sql .= " $tailOpts";
1370                 return $this->query( $sql, $fname );
1371         }
1372
1373         /**
1374          * Construct a LIMIT query with optional offset
1375          * This is used for query pages
1376          * $sql string SQL query we will append the limit too
1377          * $limit integer the SQL limit
1378          * $offset integer the SQL offset (default false)
1379          */
1380         function limitResult($sql, $limit, $offset=false) {
1381                 if( !is_numeric($limit) ) {
1382                         wfDie( "Invalid non-numeric limit passed to limitResult()\n" );
1383                 }
1384                 return " $sql LIMIT "
1385                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1386                                 . "{$limit} ";
1387         }
1388         function limitResultForUpdate($sql, $num) {
1389                 return $this->limitResult($sql, $num, 0);
1390         }
1391
1392         /**
1393          * Returns an SQL expression for a simple conditional.
1394          * Uses IF on MySQL.
1395          *
1396          * @param string $cond SQL expression which will result in a boolean value
1397          * @param string $trueVal SQL expression to return if true
1398          * @param string $falseVal SQL expression to return if false
1399          * @return string SQL fragment
1400          */
1401         function conditional( $cond, $trueVal, $falseVal ) {
1402                 return " IF($cond, $trueVal, $falseVal) ";
1403         }
1404
1405         /**
1406          * Determines if the last failure was due to a deadlock
1407          */
1408         function wasDeadlock() {
1409                 return $this->lastErrno() == 1213;
1410         }
1411
1412         /**
1413          * Perform a deadlock-prone transaction.
1414          *
1415          * This function invokes a callback function to perform a set of write
1416          * queries. If a deadlock occurs during the processing, the transaction
1417          * will be rolled back and the callback function will be called again.
1418          *
1419          * Usage:
1420          *   $dbw->deadlockLoop( callback, ... );
1421          *
1422          * Extra arguments are passed through to the specified callback function.
1423          *
1424          * Returns whatever the callback function returned on its successful,
1425          * iteration, or false on error, for example if the retry limit was
1426          * reached.
1427          */
1428         function deadlockLoop() {
1429                 $myFname = 'Database::deadlockLoop';
1430
1431                 $this->begin();
1432                 $args = func_get_args();
1433                 $function = array_shift( $args );
1434                 $oldIgnore = $this->ignoreErrors( true );
1435                 $tries = DEADLOCK_TRIES;
1436                 if ( is_array( $function ) ) {
1437                         $fname = $function[0];
1438                 } else {
1439                         $fname = $function;
1440                 }
1441                 do {
1442                         $retVal = call_user_func_array( $function, $args );
1443                         $error = $this->lastError();
1444                         $errno = $this->lastErrno();
1445                         $sql = $this->lastQuery();
1446
1447                         if ( $errno ) {
1448                                 if ( $this->wasDeadlock() ) {
1449                                         # Retry
1450                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1451                                 } else {
1452                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1453                                 }
1454                         }
1455                 } while( $this->wasDeadlock() && --$tries > 0 );
1456                 $this->ignoreErrors( $oldIgnore );
1457                 if ( $tries <= 0 ) {
1458                         $this->query( 'ROLLBACK', $myFname );
1459                         $this->reportQueryError( $error, $errno, $sql, $fname );
1460                         return false;
1461                 } else {
1462                         $this->query( 'COMMIT', $myFname );
1463                         return $retVal;
1464                 }
1465         }
1466
1467         /**
1468          * Do a SELECT MASTER_POS_WAIT()
1469          *
1470          * @param string $file the binlog file
1471          * @param string $pos the binlog position
1472          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1473          */
1474         function masterPosWait( $file, $pos, $timeout ) {
1475                 $fname = 'Database::masterPosWait';
1476                 wfProfileIn( $fname );
1477
1478
1479                 # Commit any open transactions
1480                 $this->immediateCommit();
1481
1482                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1483                 $encFile = $this->strencode( $file );
1484                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1485                 $res = $this->doQuery( $sql );
1486                 if ( $res && $row = $this->fetchRow( $res ) ) {
1487                         $this->freeResult( $res );
1488                         wfProfileOut( $fname );
1489                         return $row[0];
1490                 } else {
1491                         wfProfileOut( $fname );
1492                         return false;
1493                 }
1494         }
1495
1496         /**
1497          * Get the position of the master from SHOW SLAVE STATUS
1498          */
1499         function getSlavePos() {
1500                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1501                 $row = $this->fetchObject( $res );
1502                 if ( $row ) {
1503                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1504                 } else {
1505                         return array( false, false );
1506                 }
1507         }
1508
1509         /**
1510          * Get the position of the master from SHOW MASTER STATUS
1511          */
1512         function getMasterPos() {
1513                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1514                 $row = $this->fetchObject( $res );
1515                 if ( $row ) {
1516                         return array( $row->File, $row->Position );
1517                 } else {
1518                         return array( false, false );
1519                 }
1520         }
1521
1522         /**
1523          * Begin a transaction, or if a transaction has already started, continue it
1524          */
1525         function begin( $fname = 'Database::begin' ) {
1526                 if ( !$this->mTrxLevel ) {
1527                         $this->immediateBegin( $fname );
1528                 } else {
1529                         $this->mTrxLevel++;
1530                 }
1531         }
1532
1533         /**
1534          * End a transaction, or decrement the nest level if transactions are nested
1535          */
1536         function commit( $fname = 'Database::commit' ) {
1537                 if ( $this->mTrxLevel ) {
1538                         $this->mTrxLevel--;
1539                 }
1540                 if ( !$this->mTrxLevel ) {
1541                         $this->immediateCommit( $fname );
1542                 }
1543         }
1544
1545         /**
1546          * Rollback a transaction
1547          */
1548         function rollback( $fname = 'Database::rollback' ) {
1549                 $this->query( 'ROLLBACK', $fname );
1550                 $this->mTrxLevel = 0;
1551         }
1552
1553         /**
1554          * Begin a transaction, committing any previously open transaction
1555          */
1556         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1557                 $this->query( 'BEGIN', $fname );
1558                 $this->mTrxLevel = 1;
1559         }
1560
1561         /**
1562          * Commit transaction, if one is open
1563          */
1564         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1565                 $this->query( 'COMMIT', $fname );
1566                 $this->mTrxLevel = 0;
1567         }
1568
1569         /**
1570          * Return MW-style timestamp used for MySQL schema
1571          */
1572         function timestamp( $ts=0 ) {
1573                 return wfTimestamp(TS_MW,$ts);
1574         }
1575
1576         /**
1577          * Local database timestamp format or null
1578          */
1579         function timestampOrNull( $ts = null ) {
1580                 if( is_null( $ts ) ) {
1581                         return null;
1582                 } else {
1583                         return $this->timestamp( $ts );
1584                 }
1585         }
1586
1587         /**
1588          * @todo document
1589          */
1590         function resultObject( $result ) {
1591                 if( empty( $result ) ) {
1592                         return NULL;
1593                 } else {
1594                         return new ResultWrapper( $this, $result );
1595                 }
1596         }
1597
1598         /**
1599          * Return aggregated value alias
1600          */
1601         function aggregateValue ($valuedata,$valuename='value') {
1602                 return $valuename;
1603         }
1604
1605         /**
1606          * @return string wikitext of a link to the server software's web site
1607          */
1608         function getSoftwareLink() {
1609                 return "[http://www.mysql.com/ MySQL]";
1610         }
1611
1612         /**
1613          * @return string Version information from the database
1614          */
1615         function getServerVersion() {
1616                 return mysql_get_server_info();
1617         }
1618
1619         /**
1620          * Ping the server and try to reconnect if it there is no connection
1621          */
1622         function ping() {
1623                 if( function_exists( 'mysql_ping' ) ) {
1624                         return mysql_ping( $this->mConn );
1625                 } else {
1626                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1627                         return true;
1628                 }
1629         }
1630
1631         /**
1632          * Get slave lag.
1633          * At the moment, this will only work if the DB user has the PROCESS privilege
1634          */
1635         function getLag() {
1636                 $res = $this->query( 'SHOW PROCESSLIST' );
1637                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1638                 # dubious, but unfortunately there's no easy rigorous way
1639                 $slaveThreads = 0;
1640                 while ( $row = $this->fetchObject( $res ) ) {
1641                         if ( $row->User == 'system user' ) {
1642                                 if ( ++$slaveThreads == 2 ) {
1643                                         # This is it, return the time (except -ve)
1644                                         if ( $row->Time > 0x7fffffff ) {
1645                                                 return false;
1646                                         } else {
1647                                                 return $row->Time;
1648                                         }
1649                                 }
1650                         }
1651                 }
1652                 return false;
1653         }
1654
1655         /**
1656          * Get status information from SHOW STATUS in an associative array
1657          */
1658         function getStatus($which="%") {
1659                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1660                 $status = array();
1661                 while ( $row = $this->fetchObject( $res ) ) {
1662                         $status[$row->Variable_name] = $row->Value;
1663                 }
1664                 return $status;
1665         }
1666
1667         /**
1668          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1669          */
1670         function maxListLen() {
1671                 return 0;
1672         }
1673
1674         function encodeBlob($b) {
1675                 return $b;
1676         }
1677
1678         /**
1679          * Read and execute SQL commands from a file.
1680          * Returns true on success, error string on failure
1681          */
1682         function sourceFile( $filename ) {
1683                 $fp = fopen( $filename, 'r' );
1684                 if ( false === $fp ) {
1685                         return "Could not open \"{$fname}\".\n";
1686                 }
1687
1688                 $cmd = "";
1689                 $done = false;
1690                 $dollarquote = false;
1691
1692                 while ( ! feof( $fp ) ) {
1693                         $line = trim( fgets( $fp, 1024 ) );
1694                         $sl = strlen( $line ) - 1;
1695
1696                         if ( $sl < 0 ) { continue; }
1697                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
1698
1699                         ## Allow dollar quoting for function declarations
1700                         if (substr($line,0,4) == '$mw$') {
1701                                 if ($dollarquote) {
1702                                         $dollarquote = false;
1703                                         $done = true;
1704                                 }
1705                                 else {
1706                                         $dollarquote = true;
1707                                 }
1708                         }
1709                         else if (!$dollarquote) {
1710                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
1711                                         $done = true;
1712                                         $line = substr( $line, 0, $sl );
1713                                 }
1714                         }
1715
1716                         if ( '' != $cmd ) { $cmd .= ' '; }
1717                         $cmd .= "$line\n";
1718
1719                         if ( $done ) {
1720                                 $cmd = str_replace(';;', ";", $cmd);
1721                                 $cmd = $this->replaceVars( $cmd );
1722                                 $res = $this->query( $cmd, 'dbsource', true );
1723
1724                                 if ( false === $res ) {
1725                                         $err = $this->lastError();
1726                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
1727                                 }
1728
1729                                 $cmd = '';
1730                                 $done = false;
1731                         }
1732                 }
1733                 fclose( $fp );
1734                 return true;
1735         }
1736
1737         /**
1738          * Replace variables in sourced SQL
1739          */
1740         function replaceVars( $ins ) {
1741                 $varnames = array(
1742                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
1743                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
1744                         'wgDBadminuser', 'wgDBadminpassword',
1745                 );
1746
1747                 // Ordinary variables
1748                 foreach ( $varnames as $var ) {
1749                         if( isset( $GLOBALS[$var] ) ) {
1750                                 $val = addslashes( $GLOBALS[$var] );
1751                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
1752                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
1753                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
1754                         }
1755                 }
1756
1757                 // Table prefixes
1758                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
1759                         array( &$this, 'tableNameCallback' ), $ins );
1760                 return $ins;
1761         }
1762
1763         /**
1764          * Table name callback
1765          * @private
1766          */
1767         function tableNameCallback( $matches ) {
1768                 return $this->tableName( $matches[1] );
1769         }
1770
1771 }
1772
1773 /**
1774  * Database abstraction object for mySQL
1775  * Inherit all methods and properties of Database::Database()
1776  *
1777  * @package MediaWiki
1778  * @see Database
1779  */
1780 class DatabaseMysql extends Database {
1781         # Inherit all
1782 }
1783
1784
1785 /**
1786  * Result wrapper for grabbing data queried by someone else
1787  *
1788  * @package MediaWiki
1789  */
1790 class ResultWrapper {
1791         var $db, $result;
1792
1793         /**
1794          * @todo document
1795          */
1796         function ResultWrapper( &$database, $result ) {
1797                 $this->db =& $database;
1798                 $this->result =& $result;
1799         }
1800
1801         /**
1802          * @todo document
1803          */
1804         function numRows() {
1805                 return $this->db->numRows( $this->result );
1806         }
1807
1808         /**
1809          * @todo document
1810          */
1811         function fetchObject() {
1812                 return $this->db->fetchObject( $this->result );
1813         }
1814
1815         /**
1816          * @todo document
1817          */
1818         function &fetchRow() {
1819                 return $this->db->fetchRow( $this->result );
1820         }
1821
1822         /**
1823          * @todo document
1824          */
1825         function free() {
1826                 $this->db->freeResult( $this->result );
1827                 unset( $this->result );
1828                 unset( $this->db );
1829         }
1830
1831         function seek( $row ) {
1832                 $this->db->dataSeek( $this->result, $row );
1833         }
1834
1835 }
1836
1837
1838 #------------------------------------------------------------------------------
1839 # Global functions
1840 #------------------------------------------------------------------------------
1841
1842 /**
1843  * Standard fail function, called by default when a connection cannot be
1844  * established.
1845  * Displays the file cache if possible
1846  */
1847 function wfEmergencyAbort( &$conn, $error ) {
1848         global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding, $wgOutputEncoding;
1849         global $wgSitename, $wgServer, $wgMessageCache, $wgLogo;
1850
1851         # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
1852         # Hard coding strings instead.
1853
1854         $noconnect = "<h1><img src='$wgLogo' style='float:left;margin-right:1em' alt=''>$wgSitename has a problem</h1><p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
1855         $mainpage = 'Main Page';
1856         $searchdisabled = <<<EOT
1857 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
1858 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
1859 EOT;
1860
1861         $googlesearch = "
1862 <!-- SiteSearch Google -->
1863 <FORM method=GET action=\"http://www.google.com/search\">
1864 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
1865 <A HREF=\"http://www.google.com/\">
1866 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
1867 border=\"0\" ALT=\"Google\"></A>
1868 </td>
1869 <td>
1870 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
1871 <INPUT type=submit name=btnG VALUE=\"Google Search\">
1872 <font size=-1>
1873 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
1874 <input type='hidden' name='ie' value='$2'>
1875 <input type='hidden' name='oe' value='$2'>
1876 </font>
1877 </td></tr></TABLE>
1878 </FORM>
1879 <!-- SiteSearch Google -->";
1880         $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
1881
1882
1883         if( !headers_sent() ) {
1884                 header( 'HTTP/1.0 500 Internal Server Error' );
1885                 header( 'Content-type: text/html; charset='.$wgOutputEncoding );
1886                 /* Don't cache error pages!  They cause no end of trouble... */
1887                 header( 'Cache-control: none' );
1888                 header( 'Pragma: nocache' );
1889         }
1890
1891         # No database access
1892         if ( is_object( $wgMessageCache ) ) {
1893                 $wgMessageCache->disable();
1894         }
1895
1896         if ( trim( $error ) == '' ) {
1897                 $error = $this->mServer;
1898         }
1899
1900         wfLogDBError( "Connection error: $error\n" );
1901
1902         $text = str_replace( '$1', $error, $noconnect );
1903         $text .= wfGetSiteNotice();
1904
1905         if($wgUseFileCache) {
1906                 if($wgTitle) {
1907                         $t =& $wgTitle;
1908                 } else {
1909                         if($title) {
1910                                 $t = Title::newFromURL( $title );
1911                         } elseif (@/**/$_REQUEST['search']) {
1912                                 $search = $_REQUEST['search'];
1913                                 echo $searchdisabled;
1914                                 echo str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
1915                                   $wgInputEncoding ), $googlesearch );
1916                                 wfErrorExit();
1917                         } else {
1918                                 $t = Title::newFromText( $mainpage );
1919                         }
1920                 }
1921
1922                 $cache = new CacheManager( $t );
1923                 if( $cache->isFileCached() ) {
1924                         $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
1925                                 $cachederror . "</b></p>\n";
1926
1927                         $tag = '<div id="article">';
1928                         $text = str_replace(
1929                                 $tag,
1930                                 $tag . $msg,
1931                                 $cache->fetchPageText() );
1932                 }
1933         }
1934
1935         echo $text;
1936         wfErrorExit();
1937 }
1938
1939 ?>